Headlight Low Beams won't turn off

89LincolnLSC

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Original poster
Joined
Sep 3, 2021
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2
Location
Massachusetts
2000 TJ, after it was left with the top down in the rain, the low beams will not turn off. This was in June, the interior has dried out, but still the same. I replaced the headlight switch with a new one from the parts store, no change. Only the low beams stay on, I can turn on/off the parking lights and high beams.
When I unplug the headlight switch, the lights go out.
Unplugged, key off, from this images pins 3, 4, 6, and 8 are all hot.
With the switch plugged backed in, lights in the off position, also pin 2 is now hot.

Here's my question, did I get a bad switch (does the same thing as the original), not likely. Or, are one of the pins that are constantly getting power, not supposed to be, and it's back feeding the low beams.

Screenshot_20210826-135410_Chrome.webp
 
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Thanks for the advice. I did actually download the FSM from your link a while back. Printed the pages I thought I would need. Watched a couple videos to try to teach me how to read them. And, I still can't wrap my head around it.
I'm very mechanical, I see it and I can fix it, but electrical has always stumped me. It all looks like Egyptian writing to me!
 
Thanks for the advice. I did actually download the FSM from your link a while back. Printed the pages I thought I would need. Watched a couple videos to try to teach me how to read them. And, I still can't wrap my head around it.
I'm very mechanical, I see it and I can fix it, but electrical has always stumped me. It all looks like Egyptian writing to me!
I understand what you mean how electrical wiring schematics can look like hieroglyphics....
Each of the wires on a harness connector has a position that is identified by a number in the schematic.
You can confirm the wiring by the gauge (thickness) and of the wiring color(s).
As I suggested earlier... inspect the wiring harnesses for the headlight switch and look for signs of overheating, melting or burned connections.